Exemplary embodiments pertain to the art of rotary wing aircraft and, more particularly, to a composite driveshaft for a rotary wing aircraft.
In a rotary drive system, a driveshaft may be used to transfer torque from a rotating driving component to a rotating driven component. When the system performs at high speeds and/or high torque, it is common to use U-joints or other axial misalignment compensating devices. A U-joint, for example, might be placed at each end of the driveshaft, forming part of the connection between the driveshaft and the driving component and between the driveshaft and the driven component. Many types of misalignment compensating devices are known. Basically, they function to ensure the driveshaft is loaded only with torque, and they minimize any bending forces and compressive or tensile forces. One advantage is that by limiting bending forces, fatigue life of the driveshaft is especially increased.
The present invention is relevant to lightweight rotary drive systems for high speed and/or high torque applications, which may be especially advantageous in the aerospace industry. For example, a helicopter has a driveshaft that drives a tail rotor. There are numerous other examples of rotary drive systems in rotary wing and fixed wing aircraft. In aerospace applications, weight is a disadvantage. A driveshaft with traditional U-joints or other traditional misalignment compensating devices may be heavier than desired for the rotary drive system. This invention provides a lightweight driveshaft with an integrated axial misalignment compensating feature, which may be made from lightweight composite materials to further minimize weight.